According to the supplement published by the British Heart Foundation: European cardiovascular disease statistics, 2005 edition, CVD are the main cause of death in Europe: accounting for over 4.35 million deaths each year. Coronary heart disease (CHD) by itself is the single most common cause of death in Europe: accounting for 1.95 million deaths in Europe each year.
This supplement included a new section on economic costs estimation of CVD. Total costs of CVD is amount to 169 billion euros, of which 105 billion euros are for treating CVD in the European Union and 64 billion euros are due to lost productivity and the cost of informal care.
Plaque builds up in the arteries, also called atherosclerosis is the main cause of CVD and the most frequent cause of CHD. Atherosclerotic plaque builds up in the arteries is a common disorder of the arteries. It occurs when fat, cholesterol, and other substances build up in the walls of arteries and form hard substances called plaque.
Eventually, the plaque deposits can make the artery narrow and less flexible. This makes it harder for blood to flow. If the coronary arteries become narrow, blood flow to the heart can slow down or stop, causing chest pain (stable angina), shortness of breath, heart attack, and other symptoms.
Pieces of plaque can break apart and move through the bloodstream. This is a common cause of heart attack and stroke. Blood clots can also form around the plaque deposits. Clots block blood flow. If the clot moves into the heart, lungs, or brain, it can cause a stroke, heart attack, or pulmonary embolism.
It has been demonstrated that arterial hypertension, high levels of triglycerides and total cholesterol in the blood, and smoking are factors that contribute to the development of this affection. In recent years, researchers have found that some of these risk factors cluster together in certain people. This clustering of risk factors is known as metabolic syndrome.
People with metabolic syndrome have a clustering of the following risk factors:                Central obesity, meaning extra weight in the abdominal (stomach) area.        Trouble digesting a type of sugar called glucose (glucose intolerance). Patients with metabolic syndrome usually have hyperinsulinemia or type 2 diabetes.        High levels of low-density lipoprotein (LDL) and triglycerides in the bloodstream.        Low levels of high-density lipoprotein (HDL) in the bloodstream.        High blood pressure (hypertension).        
There is still a lot to be learned about metabolic syndrome, but doctors do know that people with metabolic syndrome have an increased risk of CVD.
Numerous studies have demonstrated that in vivo oxidation of LDL plays a central role in the development of atherosclerosis (Knight, 1995; Witzum, 1994).
Olive oil, the principal fat component of the Mediterranean diet, has been associated with a lower incidence of CHD (De Lorgeril et al., 1999; Hertog et al., 1993; Mattson and Grundy, 1985) and certain cancers (d'Amicis and Farchi, 1999; Braga et al., 1998; Trichopoulou et al., 1995; Martin-Moreno et al., 1994).
Health benefits of olive oil consumption in preventing LDL oxidation would be linked both to its antioxidant and to its high monounsaturated fatty acids content (Nicolaïew et al., 1998). Virgin olive oil phenolic compounds have strong antioxidant properties that protect olive oil from oxidation (Visioli et al., 1998; Papadopoulos and Boskou, 1991), and in addition they have shown positive health benefits (Owen et al., 2000; Manna et al., 1999). Some of the most representative phenolic compounds in virgin olive oil are hydroxytyrosol, tyrosol and some of their derivatives, which are extracted from the olive fruit during olive oil production (Brenes et al., 1999). Hydroxytyrosol is present in olive oil and has the following formula:

In co-pending patent applications EP07001791 and PCT/IB2008/000173, process and apparatus for the production of hydroxytyrosol from olives and/or olive oil extraction residues are described, which aim at the production of hydroxytyrosol-containing products or extracts to be used as a source of hydroxytyrosol in food, medical and cosmetic industries. The content of the above applications is hereto incorporated by reference.
It is well known that several sensory properties are elicited by olive polyphenols in extra virgin and virgin olive oils. The sensory aspect of these olive oils has great repercussions on its acceptability by consumers. Some phenols mainly elicit the tasting perception of bitterness; however, other phenolic molecules can stimulate the free endings of the trigeminal nerve located in the palate and also in the gustative buds giving rise to the chemesthetic perceptions of pungency, astringency and metallic attributes.
Oleuropein, the phenolic compound that makes the fruit of the olive bitter, is water-soluble rather than fat-soluble, so it get poorly transferred into the oil when the fruit is pressed, thus ranging average content of oleuropein from 1 ppb to 11 ppm in extra virgin and virgin olive oils.
Oleuropein is present in olive oil and has the following formula:

Nevertheless, a number of oleuropein related compounds are more oil soluble than oleuropein itself, and do end up at a higher content in the oil, in the form of isomer (or isomers) of oleuropein aglycon (e.g: aldehydic form of oleuropein aglycon, AOA), and dialdehydic form of elenolic acid linked to hydroxytyrosol or tyrosol, respectively named 3,4-DHPEA-EDA and p-HPEA-EDA, that are the olive polyphenols mainly responsible for the bitter taste according to Gutierrez-Rosales and co-authors, J. Agric. Food Chem. 2003, 51, 6021-6025.
Oleuropein aglycon (e.g: aldehydic form of oleuropein aglycon) is present in olive oil and has the following formula:

Frank and co-authors in J. Agric. Food Chem. 2001, 49, 231-238 disclose a procedure called “taste dilution analysis” in order to point out the sensory threshold of bitter for oleuropein derivatives. Bitterness was assessed by preparing serial dilutions of samples in water and then tasting them according to increasing concentration, until the concentration at which the diluted sample can be differentiated from water as judged in a triangle test is found. It was also shown that at least for these compounds there is no direct correlation of bitterness with the absorbance at 225 (the K225 value): Mateo et al. J. Am. Oil Chem. Soc. 2004, 81, 71-75, verified the correlation between the aldehydic form of oleuropein aglycon (obtained by hydrolysis of oleuropein with β-glucosidase from almonds purchased from Sigma) and bitterness.
Andrewes et al., J. Agric. Food Chem. 2003, 51, 1415-1420, assessed the relationship between polyphenols and olive oil pungency; p-HPEA-EDA was the key source of the burning sensation found in many olive oils.
In 2005, Beauchamp and co-authors, Nature 2005, 437, 45-46, measured the pungent intensity of p-HPEA-EDA isolated from different extra virgin and virgin olive oils confirming this molecule is the principal agent in extra virgin and virgin olive oils responsible for throat irritation.
Summarizing, any way set up in order to increase antioxidant capacity using techniques based on fortification of olive oil with olive polyphenols, should not alter oils natural organoleptic characteristics, nor increase the amount of the bitter tasting olive polyphenols, otherwise incurring with the subsequent alteration of organoleptic properties of the oil, thus causing non-pleasant taste due to excessive bitterness, pungency and/or astringency, and subsequently causing rejection from many consumers.
It is known to add polyphenols and hydroxytyrosol to food products.
U.S. Pat. No. 6,942,890 discloses a method of fortifying food products adding to such products solid matter derived from olive fruits, resulting in an increase of the level of antioxidants, particularly of olive polyphenols. This process requires the incubation during a certain time of the food product to be fortified, e.g. a vegetable oil, with solid matter derived from olives which have not been subjected to a debittering treatment, and then separating the solid from the oil by filtration. The main problem connected with this process is associated with alteration of organoleptic properties of the vegetable oil, causing non-pleasant taste when excessive bitterness and/or astringency are produced in relation when oil increases its contents of polyphenols. According to the inventors, this alteration could be avoided particularly when the final product obtained is produced adding as much a 2.5% of olive solid matter that makes extra virgin olive oils increase olive polyphenols from 145 ppm to 530 ppm as maximum.
U.S. Pat. No. 6,162,480 discloses a method of fortifying vegetable oil with antioxidants. Non-debittered olives are soaked from 1 to 30 days in vegetable oil, resulting in an increase of the level of antioxidants, particularly of olive polyphenols. According ex. 1, adding 10% non-debittered olives from Toscane were slowly stirred for 30 days with Toscane extra virgin olive oil, that makes extra virgin olive oils increase olive polyphenols from 420 ppm to 591 ppm, being this the maximum increase allowed according the invention. This method is substantially the same as the well known one used to preserve olives in olive oil, apart from the stirring.
The main problem connected with methods disclosed in U.S. Pat. No. 6,942,890 and U.S. Pat. No. 6,162,480 is that only polyphenols that are fat soluble are (partly) extracted from olive solid matter or olives into oil.
U.S. Pat. No. 6,746,706 discloses a method of fortifying food compositions (spreads, vinaigrette and tomato sauce), where such compositions containing 20-100 wt % of an aqueous phase characterized by an enhanced content of tyrosol and hydroxytyrosol in aqueous phase being at least 15 ppm. Nevertheless, this method is scarcely effective: none of the patent examples shows that the prepared food compositions reach concentrations in the water phase higher than 50 ppm for hydroxytyrosol and tyrosol together.
U.S. Pat. No. 6,361,803 discloses (ex. 13) a method characterized by using an olive extract produced according ex. 4 to allow an enhancement of antioxidant activity in an oil. Nevertheless, the antioxidant capacity of the control sample, 0.18 mM Trolox equivalent per gram, was only enhanced approximately three times by the method of the invention, 0.53 mM Trolox equivalent per gram.
U.S. Pat. No. 6,361,803 requires the use of organic solvents, particularly polar solvents, in order to produce an olive extract containing hydroxytyrosol with an acceptable purity grade. Polar aqueous solvents are selected among methanol, ethanol, acetonitrile or acetone, while polar organic solvents are selected, for example, among esters, amides, dimethyl sulfoxide, dioxane, DMF and their mixtures. The use of organic solvents, for example methanol that is a toxic solvent, is inconvenient, particularly when the final product obtained is to be used in the alimentary field.
The main problem connected with this process, in addition to the problem arising from the use of organic (and in some cases toxic) solvents, is that re-dissolution of olive extract rich in hydroxytyrosol disclosed on ex. 13 (antioxidant composition) needs water/ethanol/acetic acid mixture to previously dissolve the extract and give a stable emulsion in the oil to be fortified, being this procedure inconvenient in alimentary field.
IT 01326553 discloses a fortified olive oil obtained by addition of extracts deriving from olive leaves or vegetation water to olive oil. The extracts are rich in all types of polyphenols, i.e. they have a low purity of hydroxytyrosol. In fact extracts from leaves contain almost no hydroxytyrosol. The problem of this patent and of the previously disclosed patents mainly resides in the low amount of free hydroxytyrosol with respect to the total amount of polyphenols: the lower the amount of hydroxytyrosol with respect to other polyphenols, the higher is the bitterness (i.e. the bitter taste) of the fortified product for the same amount of free hydroxytyrosol in the oil.
U.S. Pat. No. 5,998,641 relates to a process of increasing the general content of polyphenols in olive oil without increasing the bitter taste. To this purpose, olive oil is emulsified with a water solution containing polyphenols and a debittering enzyme (e.g beta-glucosidase from almonds purchased from Sigma (ex.1)). Water is then removed by evaporation or ultrafiltration to avoid loss of those resulting polyphenols that are soluble in water and insoluble in oil. The problem of this method is that it is very long (at least 24 hours according to the examples and up to 100 hours) and that all the products of the enzymatic reaction, including oleuropein aglycon and sugars, remain in the oil.
It should be remarked that hydrolysis of oleuropein by β-glucosidase (e.g from almonds, purchased from Sigma), has been normally used by several authors for the preparation of an isomer (or isomers) of oleuropein aglycon that was found to be bitter with a threshold of 50 μmol (Frank and co-authors J. Agric. Food Chem. 2001, 49, 231-238). Also, Mateo et al. J. Am. Oil Chem. Soc. 2004, 81, 71-75, verified the correlation between the aldehydic form of oleuropein aglycon (obtained by hydrolysis of oleuropein with β-glucosidase from almonds purchased from Sigma) and bitterness. In other words, in U.S. Pat. No. 5,998,641 the result of the enzyme hydrolysis is a plurality of by-products including polyphenolic compounds that upon tasting give a bitter taste to the oil but that are not detectable with the K225 test.
Also it should be considered that water removal by evaporation has a negative influence on the sensory attributes (qualitative characteristics) of virgin olive oils because most of the volatile substances responsible of the unique aroma of this oil will be extracted together with the water during the evaporation process.
Summarizing, the above mentioned techniques are either too long or too complex, or too harsh for alimentary field, or all of the above; in addition the amount of hydroxytyrosol that can be incorporated in the edible oil without having too much bitter taste, pungent intensity or sugar and by-products content, and without losing aromatic volatile compounds, is too low to effectively protect LDL against oxidative modification to any important extent. It has also to be noted that all the above mentioned techniques allow to obtain an olive oil with an increased content of total olive polyphenols but with a low content in hydroxytyrosol with respect to the total olive polyphenols content, as present in the oil, due to the fact that most of the polyphenols incorporated to the oil are secoiridoids, oleuropein related compounds characterized by a higher oil solubility than hydroxytyrosol, that are consequently incorporated to the oil, as oleuropein aglycon (AOA), 3,4-DHPEA-EDA and p-HPEA-EDA, at a higher content than hydroxytyrosol, and that are those olive polyphenols mainly responsible for the bitter taste and pungency. The incorporation of these secoiridoids, able to produce undesirable changes in the organoleptic properties of the olive oil, is in fact directly related with the source of olive polyphenols used in all the above mentioned techniques, which in fact present a low content in hydroxytyrosol and/or a low purity degree.